[unreadable] This Exploratory/Developmental Research (R21) application proposes a dramatic advance in the state of the art of micron-scale anatomical and functional biomedical imaging by applying the principles of engineering optimization to system design in Optical Coherence Tomography (OCT). We propose three key innovations in OCT system design which, once demonstrated separately and then combined, will result in a new generation of OCT imagers with increased sensitivity, acquisition rate, and robustness as compared to the current state of the art. These innovations build upon recent work in the field on Fourier-Domain OCT, an alternative approach to OCT data collection which takes advantage of parallel array detection technology in place of single sensors as conventionally used. However, the proposed approach extends well beyond the current state of the art in Fourier-Domain OCT by introducing specific design innovations which optimize system sensitivity (defined as the signal-to-noise ratio for an ideal reflective sample, and which can be traded off for acquisition rate) and robustness (defined as system manufacturability and durability), in contrast to current designs which exhibit severe limitations in both areas. This research and development should result in a compact, high sensitivity, robust complex Fourier-Domain OCT engine that readily can be incorporated into ongoing clinical (e.g. ophthalmic, endoscopic) and biological (e.g. small animal imaging) applications. [unreadable] [unreadable]